Don't flush whole TLB if only a small kernel range is requested.
Signed-off-by: NMax Filippov <jcmvbkbc@gmail.com>

there is a small possibility that wake_up of softirq thread
happens between local_irq_enable() and set_cpu_online(). In
this case affinity of the thread changes to fallback affinity
(i.e. CPU0). This may be a source of problems.

The patch kills that possibility.
Signed-off-by: NKirill Tkhai <tkhai@yandex.ru>
Signed-off-by: NMax Filippov <jcmvbkbc@gmail.com>

Signed-off-by: NMax Filippov <jcmvbkbc@gmail.com>
Signed-off-by: NChris Zankel <chris@zankel.net>

This is largely based on SMP code from the xtensa-2.6.29-smp tree by
Piet Delaney, Marc Gauthier, Joe Taylor, Christian Zankel (and possibly
other Tensilica folks).
Signed-off-by: NMax Filippov <jcmvbkbc@gmail.com>
Signed-off-by: NChris Zankel <chris@zankel.net>